Compressed air circuit breaker



NOV. 3, 1953 o w 2,658,128

COMPRESSED AIR CIRCUIT BREAKER Filed Aug. 4, 1949 2 Sheets-Sheet l T E ID.

27 Ill 7 I l H a. L

L l N Hm I I H1142 I. Hit/a I f -1 I BY(Q9' ATTORNEY Nov. 3, 1953 2,658,128

H. FORWALD COMPRESSED AIR CIRCUIT BREAKER Filed Aug. 4, 1949 2 SheetsSheet 2 IIIIII III/n INVENTOR HAA/(QNFRW/MD ATTORNEY l atenteci Nov. 3, 1951?;

2,658,128 COMPRESSED AIR CIRCUIT BREAKER Haakon Forwald, Valhalla, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget,

Vasteras, Sweden,

a Swedish corporation Application August 4, 1949, Serial No. 108,522

Claims priority, application Sweden August 7, 1948 3 Claims.

In spite of the recent development of electrical circuit breakers it is still very difiicult to produce circuit breakers able to carry large currents and interrupt the large short circuit currents now common on the generator side in modern power stations. It is especially difiicult to procure circuit breakers able to interrupt the short circuits up to 100 ka, which may occur.

The present invention relates to a circuit breaker, which is able to carry the largest service currents which may occur and also the largest short circuit currents. According to the invention the circuit breaker consists of two or more electrically series-connected breaking gaps, which, however, are connected pneumatically in parallel, the compressed air being delivered to them simultaneously through parallel air delivery pipe lines or channels. The main breaking gaps may, however, be bridged over by parallel contacts, which are electrically connected in parallel, but, with respect to the delivery of the breaking air, are connected in series with the main breaking gaps.

On the accompanying drawing, a number of forms of the invention are shown, where Figs. 1a and lb show one phase of a multiphase circuit breaker, Fig. 2 shows one phase of a compressed air circuit breaker with two series-connected breaking gaps and a single bridging contact pair connected in parallel with them, and Fig. 3 shows one phase of a compressed air circuit breaker with two series-connected breaking gaps and two parallel-connected bridging contact pairs, which are pneumatically connected in series with the main breaking gaps.

In Figs. 1a and 1b, I designates the compressed air container and 2 the air blast valves and 3 a frame work carrying the container l and the circuit breaker with its disconnecting switch. The poles of the circuit breaker consist of the main breaking gaps 4, each of which has a movable contact 5 and a sleeve shaped stationary contact 6. The main breaking gaps are enclosed in insulating cylinders 1, which in turn are carried by insulating cylinders 8, which rest on insulating cylinders 9. Between cylinders 8 and 9, however, a metal part I0, is connected with one of the lines l3 of the circuit breaker. The insulating cylinders 9 enclose the movable bridging contacts II, which are arranged to engage in the stationary bridging contacts 12, which are connected with a strip, to which the disconnecting switch arm I4 is attached. The arm I4 is operated by an operating lever I 5, and it engages in the contact l6 attached to the insulator H. The circuit breaker pole itself is carried by an insulator l8 resting on the frame 3.

Conductors I9, 20 and 2| are also provided. By means of the conductor l9 the breaking pair at the extreme right is connected with the line l3 and this breaking pair is by means of the conductor 20 joined with the breaking pair in the middle pole, and further the latter breaking pair is by means of the conductor 2| joined with the main breaking gap in the left pole, which latter is joined over the line 22 with the strip l2 and thus with the disconnecting switch arm :4. The bridging contact pairs H and 12 are, however, mutually connected in parallel so that their movable contacts are joined with or formed in the part It, whereas the stationary contacts are joined with or formed in the part l2. The flow of current through the circuit breaker will thus be as indicated on the drawing by the arrows. Instead of arranging a valve for each pole as shown on the drawing, it is of course possible to arrange a valve common for all poles.

In Figs. 2 and 3 similar parts are designated by the same numbers as in Figs. 1a and 1b. In the arrangement shown in Fig. 2 the main breaking pairs 5', 6' are arranged in two parallel cylinders l, which at the lower end are joined by means of a pipe 23, which in turn is attached to the upper end of the cylinder 8, this cylinder being attached to a metal part Ill resting on the cylinder 9, which cylinder in turn is attached to the strip IE, on which the disconnecting arm I4 is journalled. For the two breaking gaps in each phase a common bridging contact II is provided. The whole circuit breaker is carried by the insulator It.

The arrangement according to Fig. 3 differs from that of Figs. 1a and 12) only in that in each phase two series-connected breaking pairs 5", 6" are arranged, each being pneumatically coupled in series with a parallel contact, which two parallel contacts ll", I2" are mutually connected in parallel and connected in parallel with the two breaking gaps. The main breaker pairs are arranged in two parallel cylinders 'l" and are connected by a conductor 20 attached to the upper end of cylinders 8" which are attached to the metal part It" resting upon the cylinders 9" which latter are attached to the strip [2" to which the disconnecting arm I4 is journalled.

I claim as my invention:

1. A compressed air circuit breaker comprising a plurality of pneumatically operated main breaking gaps, means for electrically connecting said gaps with each other in series, at least one pneumaticall operated bridging contact, means connecting said contact electrically in parallel to the whole series of the main breaking gaps, means connecting said main breaking gaps mutually in parallel with respect to the connectingsaid gaps rpnemnatically in, series. with said bridging contact.

2. A compressed air circuit breaker comprising a plurality of main breaker gaps arranged side, by side, means connecting said gaps electrically in series with each other, a single=bridging contact, means connecting said bridgingcontactelectrically in parallel with saidibrealelt:gaps aapasa sage for the supply of compressed air tor said; bridging contact, and passages-iron thesupply of, air from said bridging contact to said gaps to supply air in parallel to said main'gapsfrom: said bridging contact 3. A compressed air circuit breaken comprisair flow, and means ing a plurality of main breaker gaps arranged side by side, means electrically connecting said gaps in series with each other, an equal number of bridging contacts, means electrically connecting said bridging contacts in parallel with said breaker, gaps passages. for, the, supply of compressediainto said bridgingcontacts; and a passage for the supply of air from each of said bridging contacts to one of said breaker gaps to supply air in parallel to said main breaker gaps from said; bridging; contacts.

HAAKON FORWALD.

Referoncesfliteab in the file of this patent UNITED-STATES PATENTS Number Name Date 2,293,319 'Ihommen Aug. 18, 1942 2,353,555,- Thommen Nov. 9, 1948 

